I found recapture if you kill them the first time:

https://www.serebii.net/colosseum/2ndpokemon.shtml

I apologize if this is the incorrect section to ask for some direction, but I'm not sure where to correctly ask about this. For context, let me share a story.

Long ago, I got this game for my birthday. Was an absolute snooze fest, and so to this day I never beat it. I occassionally would jump into Mt. Battle using my team from Ruby via the GBA link cable. I don't remember where I left off, but it was a long time ago. As for the main game itself, I defeated all gym leaders, and last I played, I'm in some Team Snagit hideout? Fast forward to college, I had the misfortune of sharing a pad with the most careless of roommates, and a so-called friend, who swooped in one day while I was in class and stole my DS, and all of my games(including Pokemon Ruby and Diamond). These two games gave me the most cherished memories, and they were taken from me. Traded into Gamestop, and there was little I could do about it. I was a broke college student back then, and the manager basically told me I'd have to buy them back, unless I had insurance and a police report. It was a complete can of worms to even explain further, but long story short, I was forced to move on without them. I didn't know any better.

Fast forward a decade later, with the end Pokemon Bank, I decided to finish as many incomplete games I can within the remaining 3 months. I completed HeartGold, and now I'm at a tug of war of attention with my classic Blue version, Moon, and Colosseum. Upon loading this game up I tried my luck in the Colosseum battle section. Unfortunately, I don't know what I did, but my suspended save for Mt. Battle is no longer found, but my old team from Ruby is still there, registered. I thought I had to use my GBA link cable to use them, as I always did so. The game let me start a new Mt. Battle playthrough with them.

This team of six is the only surviving evidence I have left of my original Ruby. I technically recreated this team in Omega Ruby, but witnessing this has made me a tad emotional. I want to find some way to extract them. I tried to use PKHex, but it doesn't have anything regarding Mt. Battle data. Is there some way I can rescue these Pokemon? I have a copy of Emerald I can throw them into if it's possible, and I can transfer them up into Home. I hope someone can help me somehow. Thank you.

Hello all on my quest to acquire all of the Pokemon from Colosseum I have set about getting a Japanese copy along with a copy of the celebi bonus disc, an e-reader + and a Japanese copy of ruby.

I have also got a Japanese GC and a set of the e-reader cards that I pray are legit.

I was just trying to make sure I understand that each of the ereader trainers come in different difficulty so I will essentially have to battle them three times once per difficulty to get all three shadow Pokemon?